Comparing the Conventional Stated Preference Valuation Technique with a Prediction Approach

Stated preference techniques have been used to place values on public goods by directly asking individuals to provide their personal values and opinions. This method has consistently resulted in the emergence of hypothetical bias. Several insights from the psychology literature suggest that social desirability bias, a contributor to hypothetical bias, occurs when individuals face such direct questions. However, replacing the direct questions with an indirect one that asks for their predictions about other’s values can potentially eliminate this bias. In this study we employ both questioning formats in a choice experiment to make comparisons between the stated responses. Predicted willingness to pay is 2.5 and 3.1 times smaller than hypothetical values indicating predictions to be a more accurate measure of actual values. The study further highlights the vulnerability of the conventional approach to a social desirability bias as it allows normative motives to distort respondents’ decisions, which in turn generates preferences for environmental attributes that are misleading.